Bacterial classification, strucutre, nutrition and growth Flashcards
What is the smallest infectious particle called?
virus
How big are viruses?
18-600 nanometers
What do viruses need to replicate?
a host cell (i.e it is a true parasite)
Are bacteria prokaryotic or eukaryotic
prokaryotic
How big are bacteria?
1-20 micrometers
How many cells do bacteria have?
one they are unicellular
Do bacteria have a nuclear membrane?
no, in fact they have no membrane bound organelles
How do bacteria reproduce?
via asexual division
Are fungi eukaryotic or prokaryotic?
eukaryotic
Do fungi have membrane bound organelles?
yes
What do the membranes of fungi have in them?
a unique sterol called ergosterol?
what is the sterol found in the membrane of fungi?
ergosterol
How do fungi undergo replication?
Unicellular fungi like yeast undergo asexual rep.
Filamentous (like mold) can replicated sexually or asexually?
What type of fungus can replicate asexually?
both filamentous and unicellular
What type of fungus can replicate sexually?
filamentous
Are parasites eukaryotic or prokaryotic?
eukaryotic
How big are parasites?
1-2 micrometers (protozoa) to 10 meters (tapeworms)
What is the most complex microbe?
parasites
Are parasites unicellular or multicellular?
they are both :)
What is a great therapeutic drug target on fungi?
there sterol called ergoterole
What are the 7 ways you can classify a bacteria?
shape arrangement cell wall structure antigenic (i.e absence or presence of specific antigens) Metabolism Ability to lyse erythrocytes Fermentation of sugars
What are the three shapes a bacteria can be in?
spherical-coccous
Rod-Bacillus
spiral-spirillum
What are the 2 arrangments bacteria can be in?
chains- single division plane
clumps- multiple division plane
What are the three different cell wall strucutures a bacteria can have?
Gram positive
Gram negative
Acid fast (wax like nearly impermeable cell walls)
What is the least effective way of classifying bacteria?
arrangements
What is the most important way to identify bacteria?
cell wall structure
What can an acid fast stain tell you?
if you have TB
Staph forms clumps or chains?
clumps
Strep forms clumps or chains?
chains
What are the three ways you can classify bacteria based upon metabolism?
aerobic
facultative anerobe
anearobic
(Blank) can grow with or without oxygen because they can metabolise energy aerobically or anaerobically. They gather mostly at the top because aerobic respiration generates more ATP than either fermentation or anaerobic respiration
Facultative anaerobe
What are the 2 ways to classify a bacterials ability to lyse erythrocytes?
hemolytic and nonhemolytic
How do you classify a bacterias abilty to ferment sugars?
fermenter
non-fermenter
What are the four group habits that you use to classify microbial pathogens?
extracellular
intracellular
toxin producer
pyogenic cocci
What are 2 main characteristics of extracellular microbial pathogens?
they cannot survive inside the phagocyte
they are often controlled by phagocytes
What are the 2 main characteristics of intracellular microbial pathogens?
grows inside phagocytes
often controlled by T cell based immunity
How do you know if a microbial pathogen is a toxin producer?
symptoms will appear at distant sites
How do you know if a microbial pathogen is a pyogenic cocci?
pus will form
What can the system affected and measns of acquisition (i.e foodborne, zoonotic, etc) tell you?
tell you what microbial pathogen you are dealing with
T or F
Intracellular bacteria can live inside a resting macrophage?
T
What are some differences in structure between bacteria and humans?
cell wall cytoplasm nucleic acid synthesis protein synthesis metabolic pathways
What is the importance of the differing structures between humans and bacteria?
the structures that only the bacteria have can be targeted for therapeutics.
Bacterial structures contribute to (blank). How?
pathogenesis
inflammation, resistance to host factors, adherence to cells and tissues
Explain the structure of a bacterial chromosome
its a single double-stranded cirlce with no nucleus or nuclear membrane
What is a plasmid? What does it do?
small, extra chrmosomal DNA
may encode extra, non-essential functions (i.e toxins, or antibiotic resistance)
Describe the structure of a bacterial ribosome
30S + 50S-> 70s
Are bacterial proteins similiar to eukaryotic proteins?
NOOO they are very different
Does the cytoplasmic membrane of a bacteria have sterols?
no EXCEPT for mycoplasma, that has cholesterol in it that it steals from humans
What is the basic structure of the cell wall of all bacteria made by?
peptidoglycan
What is the sugar backbone of peptidoglycan made up of?
N actetyl glucosamine and N-acetylmuramic acid in a repeating dissacharide unit
THere are four peptides attached to the (blank) of the sugar backbone of peptidoglycan. What do you call the four peptides?
N-acetylmuramic acid
a stem peptide
How do you link a stem peptide to a fellow stem peptide of another repeating disaccharide backbone?
via a glycine transpeptidization cross bridge.
How do you synthesize peptidoglycan?
in the cytoplasma you create a water soluble precursor that attaches to the insides of the cytoplasmic membrane and then flips to the outside of this membrane where it will cross link 3 dimensionally
What do you call the step in peptidogycan biosynthesis where you have formation of linear polymers outside the membrane?
trans glycosylation
What do you call the step in peptidoglycan biosynthesis where you have cross-linking of polymers into a three-dimentional matrix?
transpeptidization
Explain Peptidoglycan synthesis in detail?
you have UDP muramic acid and add a pentapeptide and attach that sugar to a lipid on the inside of the cytoplasmic membrane. This will flip to the outside and you will add the second sugar which is GlcNAc then crosslinking wil occur via transpeptidization
What does vancomycin and beta lactam do?
inhibits transpeptidization so you wont get crosslinking and thus it fucks up the peptidoglycan and the bacterial cell wall
How do you stain bacteria to determine if it is gram positive or gram negative?
You fix the bacteria to the slide via heat or alcohol. Then you pour crystal violet onto the cells to stain all bacteria cell walls blue. Then you use grma iodine to trap the blue dye into gram positive cell walls.
Then you use decoloroizer to remove the crystal violet from gram negative cell walls. Then you had Safranin to stain the gram negative red
What color is gram negative bacteria?
red
What color is gram positive bacteria?
blue
a gram positive reaction relies on the integrity of the (blank)
cell wall
T or F
a gram positive bacterium can stain gram negative
T
T or F
a gram negative bacterium can stain gram positive
F
T or F
a gram negative bacterium never stains gram positive
T
What can cause a breach in cell wall integrity?
old age
antibiotics
too much heat fixation
If you are trying to determine whether you cell is gram positive or gram negative, what dont you want to do?
take a sample after you start someone on antibiotics
What is the primary constituent of the cell wall of a gram positive bacteria?
peptidoglycan
Is the cell wall of gram positive bacteria thick or thin?
thick and multilayered
How can you fuck up gram positive cell wall?
with lysozome
What do you call a cell whose cell wall has been taken away?
a protoplasm
What is the function of teichoic acid
The main function of teichoic acids is to provide rigidity to the cell-wall by attracting cations such as magnesium and sodium
What is teichoic acid made up of?
polymer of polyol phosphates, covalently linked to peptidoglycan
What is lipoteichoic acid made up of?
teichoic acid with fatty acid anchored in cytoplasmic membrane
What does lipoteichoic acid do?
stimulate innate host responses in manner simliar to endotoxin of gram negative bacteria.
Where do you find Teichoic acids?
in gram positive cell walls
What is worrisome about LPA?
it can cause a bad inflammatory reponse when it gets broken down
What is super cool about gram negative bacteria and their cell wall?
There is 2 layers to make it!
Is peptidoglycan prominent in gram negative bacteria?
no it is a very small part of the cell wall by weight
Do gram negative bacteria have teichoic acids or lipoteichoic acids?
NO
What is the outer membrane (which is unique to gram negative bacteria) used for?
barrier to large molecules (i.e. lysozyme and hydrophobic molecules (some antibiotics))
Which layer of the gram negative membrane is this:
phospholipids similiar to other bacterial membranes
Inner layer
Which layer of the gram negative cytoplasmic membrane is this:
composed primarily of lipopolysaccharide (LPS)
outer layer
What is the outter layer of the cytoplasmic membrane made up of?
LPS
Since gram negative bacteria needs to have nutrients but has that super thick cytoplasmic membrane how do nutrients get in.
Through porins that allow for the passage of small hydrophilic molecules (this is a target for drug therapy)
Can you kill gram negative bacteria with lyosozyme?
no!
LPS is an (blank) and is found on the outter membrane of the cytoplasmic membrane of gram negative bacteria
endotoxin
What are the three components of LPS?
Lipid A
Core polysaccharide
O antigen
What part of the LPS is responsible for its toxic properties?
Lipid A
What is lipid A bound by?
polymyxin B (an antibiotic)
What is the core polysaccharide component of LPS made up of?
9-12 sugars and an unusual sugar 2-keto-3-deoxy-octanoate (KDO)
What is the O antigen component of LPS made up of?
50-100 repeating units of 4-7 sugars
What part of LPS is highly antigenic and used to classify bacteria?
O antigen
What are the last 2 peptides of the pentapeptide of peptidoglycan?
alanine and alanine
(blank) interferes with the dephosphorylation of C55-isoprenyl pyrophosphate, a molecule that carries the building-blocks of the peptidoglycan bacterial cell wall outside of the inner membrane
Bacitracin
What type of gram negative bacteria does not have an O antigen?
Neisseria
What is lipoteichoic attached to?
remember this is only found on gram positive
the plasma membrane of the bacteria
What is wall techoic attached to?
remember this is only found on gram positive
to the cell wall
What is periplasm and where do you find this ?
periplasm is a space found between the outter membrane and inner membrane of gram negative bacteria.
What besides periplasm is found between the 2 layers of the cell membrane
peptidoglycan
What makes up the cell wall of gram negative bacteria?
LPS (outer membrane) and peptidoglycan
Do gram-positive bacteria of an outer membrane?
no
What is the cell wall like on gram-positive bacteria? what about gram-negative?
THICK
Thin
Where do you find LPS/endotoxin?
in gram-negative
Where do you find teichoic and lipoteichoic acids?
in gram positive
Where do you find spores?
In some genera of gram-positive
Where do you find capsules?
occasionally on gram pos or gram neg
What does penicilin affect, gram pos or gram neg?
gram pos
Where do you find exotoxins?
common in gram pos
sometimes in gram neg
What are the capsules of bacteria made up of? There is one exception,, what is it?
polysaccharides
Bacillus anthracis made up of poly-glutamic acid
Can phagocytes chew up a capsule?
no
What makes for an excellent vaccine target?
capsules
Since the capsule is made up of sugar what does this allow for our immune cells to do?
it allows for T-independent immune response by elliciting B cell proliferation by having B cells bind directly to the external capsule
What are flagella?
rope-like propellers that are made up of coiled proteins subunits and provide motility
What are fimbriae?
Hair like structures composed of protein subunits (pilin) and work as adherene factors.
What does this "under special circumstances": F pili (sex pili) acts as a tube for transfer of bacterial chromosomes between cells.
Fimbriae
What is a very important mycobacteria?
mycobacterium tuberculosis
Mycobacteria have peptidoglycan that is intertwined with polymer of (blank)
arabinogalactan
What is mycobacteria covered in?
Wax lke lipid coat-mycolic acid
cord factor
Wax D
What is mycobacteria resistant to?
disinfectants and many stains
How can you classify mycobacteria via staining?
with acid fast
What makes mycoplasma a weirdo bacteria?
it has no peptidoglycan and it has steroles that it took from it host membrane
What gram positive bacteria make spores?
clostridium and bacillus
Are spores made by gram negative bacteria?
nO
What do spores allow bacterium to do?
survive harsh environments
What makes up spores?
complete copy of chromosome
minimal proteins and ribosomes
high concentration of dipiclonic acid (unique to spores) bound to Ca++
What is unique to spores?
dipiclonic acid
What triggers sporulation?
depletion of nutrients
How do you trigger germination of spore producing bacteria?
stress, water and a triggering nutrient
What are the nutritional requirements for bacterial growth?
carbon nitrogen growth factors (b complex vits) inorganic ions oxygen
What are the physical requirements for bacterial growth?
oxidation-reduction potential
temperature (psychorophillic, mesophi, thermophilic)
hydrogen ion conce.
osmotic conditions
What is the ideal temp range for psychrophilic bacteria?
-5-30 degrees celsius
What is the ideal temp range for mesophilic bacteria?
10-45 degrees celsius
What is the ideal temp for thermophlic bacteria?
25-80 degrees celsius
What is the most efficient way to produce energy and what is the terminal acceptor?
Aerobic
oxygen
What is the least efficient way to make energy and what is the terminal electron acceptor?
fermentation
organic molecule
What is the terminal electron acceptor of anaerobic respiration?
inorganic compound (i.e. nitrate, sulfate or carbonate)
What do obligate aerobes need?
molecular oxygen for metabolism and growth
What might obligate aerobes produce?
superoxide dismutase and catalaste to detoxify superoxide radicals and hydrogen peroxide
What are facultatively anearobic bacteria?
grow in the presence or absence of oxygen. Oxygen is terminal electron acceptor. Utilizes other electron acceptors under anaerobic conditions
What are obligate anaerobes?
oxygen is toxic and an inorganic compound is the terminal electron acceptor
How do determine bacterial mass?
dry weight or turbidity (optical density)
How you determine the cell number of bacteria?
direct counting by microscopy
quantitative culture
How do you do quantitative cultures?
prepare serial dilutions
culture in petri plates
directly count colonies
How do you do bacterial enumeration by microscopy?
add bacterial suspension to a 25 large grid square.
calculate volume of bacterial suspension.
count number of cells in large square. times that number by the volume and that equals the cell number in a millimeter.
How do you determine bacterial enumeration by colony counts?
you count number of colonies on plate and times it by the reciprical of the dilution
Ex. 32 colones at dilution of 1/1000= 32 X 1000= 32,000
What are the phases of the bacterial growth curve?
lag phase, exponential growth, stationary phase and death or decline
What happens during the lag phase of bacterial growth?
What does the graph look like here?
increase in cell size
little or no cell division
adjustment to replenish pool of metabolites
Flat
What happens during the exponential growth phase of bacterial growth?
What does the graph look like here?
balanced growth
cell number and mass increase simultaneously
Exponential increase
How is the growth rate of bacteria exressed?
by natural exponential function (doubling time)
When is bacteria most suceptible to penicillin?
during the exponential growth phase
What does growth rate depend on?
bacterial species and environment
What happens during the stationary phase?
What does the graph look like here?
accumulation of waste, exhaustion of nutrients
Flat
What does the bacterial death look like on the graph?
logarithmic decline
Bacteria may differ greatly in the efficiency of their energy production. Which of the following terminal electron acceptors is on a pathway that would maximize total ATP production?
oxygen
Transpeptidases are targets of the beta lactam class of antibiotics. What is the function of transpeptidases in cell wall synthesis?
Generate cross-linking between the peptides on peptidoglycan to produce a complex matrix
Porins have been identified as potential vaccine targets for Neisseria meningitidis and Neisseria gonorrhoeae. What is the location of porins in the bacterial cell wall?
The outer membrane of gram-negative bacteria
